Radial Bearing for Mounting a Shaft

ABSTRACT

The invention relates to a radial bearing for mounting a shaft, comprising the following features:
         several bearing shells which are curved according to the radius of the shaft and whose inner surface forms the plain bearing surfaces;   a housing enclosing the bearing shells;   at least one of the end regions of the respective bearing shell as seen in the circumferential direction is held in an interlocking manner on the housing in such a way that expansion and/or displacement of the end region or the entire bearing shell is possible;   means for setting the curvature of the individual bearing shell.

The invention relates to a bearing for mounting a shaft in the radial direction. Such bearings are known in a large number of varieties.

In the present case, a bearing with a housing is concerned which is lined with bearing shells. There are bearing shells which represent closed bushings. There are also linings consisting of several shells, which respectively represent segments and which are joined into a more or less closed ring within the housing.

The invention is based on such segment bearing shells. The individual segments are fixed to the inside surface of the housing, e.g. by gluing or screwing, and therefore in a non-positive way.

This leads to numerous disadvantages. One important disadvantage lies in the type of fixing itself. As a result, gluing is often not durable. Screwed joints can also loosen over time. Moreover, the bearing clearance and the segment shell curvature cannot be adjusted, so that optimal lubrication is not ensured.

The invention is based on the object of providing a radial bearing which comprises plain bearing areas formed by segment shells, in which the bearing clearance and the segment shell curvature are adjustable and which has a mechanically simple configuration.

This object is achieved by the features of claim 1.

The interlocked fixing of the bearing shells in accordance with the invention allows a certain expansion and/or displacement of at least the end region of the individual shells. This property plays a role in the adjustment of the segments. The curvature and the position of the shelves relative to the shaft can be adjusted. For this purpose, a packing plate or a comparable spacer element of selected thickness can be inserted between the individual shells and the housing. This preferably occurs between the two ends of the respective shell, as seen in the circumferential direction, preferably in the middle region. Alternatively, a shell holder or a comparable clamping or holding element which fixes the shell in relation to the housing can be guided from the outside through the housing and also through the respective shell. The segment shell curvature and the bearing clearance can be set with the shell holders or comparable clamping or holding means in combination with respective spacer elements. A certain flexibility of the shell is of decisive importance in this respect. This flexibility allows that the segment shell curvature can be varied during mounting by clamping or holding elements between the shell and the housing in combination with respective spacer elements between the shell and housing. As a result, the bearing shells will be brought to their respective shape relevant for the bearing function only during mounting. This procedure offers the possibility to reduce the precision requirements in segment production and to subsequently adjust the bearings after a certain operating time in a simple way.

The state of the art and the invention are shown in closer detail in the drawings, which show the following in detail:

FIG. 1 shows the hydrodynamic pressure buildup in a cylindrical plain bearing;

FIG. 2 shows a shaft with a bearing in accordance with the invention in an axially perpendicular sectional view;

FIG. 3 shows the subject matter of FIG. 2 in a perspective view;

FIG. 4 shows a section of the subject matter of FIG. 2.

FIG. 5 shows a schematic illustration of an axial sectional view through a radial bearing with an adjusting device for varying the curvature of a bearing shell.

FIG. 1 shows a revolving shaft 1. It is mounted by a plain bearing 2. A bearing clearance 3 is disposed between the two, which is formed by the outer surface 1.1 of the shaft and the bearing surface 2.1 of the bearing.

The bearing clearance 3 tapers during the rotation of the shaft 1 in the circumferential direction U. A pressure field 4 is built up over the bearing clearance. It leads to an eccentricity e of the shaft 1 relative to the bearing 2.

The radial bearing in accordance with the invention and according to FIGS. 2 and 3 comprises a number of bearing shells 2 with bearing surfaces 2.1. The bearing shells can consist of any material, e.g. plastic or metal. Polyurethane or any other polymer is suitable as a bearing material in configurations that use synthetic material.

The bearing shells 2 are made of a solid sleeve which was subdivided after production into the segments that are shown here.

The bearing shells are enclosed by a housing 5 which consists of steel for example.

Shell holders 6 are provided as clamping or holding elements for fixing the bearing shells 2 to the housing. They comprise a holding strip 6.1 which extends over the axial length of the bearing shells and which engages into recesses of the mutually adjacent bearing shells. The depth of the recess and thickness of the holding strip 6.1 are dimensioned in such a way that the inside surface of the holding strip 6.1 is flush with the bearing surface 2.1.

Each shell holder 6 further comprises a plurality of holding pins 6.2. They are guided through the housing 5 and through the bearing shell 2 and fixed to holding strips 6.1. They protrude beyond the outer jacket surface of the housing 5. They comprise a thread with which a screw 6.3 is screwed together.

Generally, the shell holder 6 will consist of metal. The holding strip 6.1 can consist of a composite material, the radially inner region of which is made of the same or a similar material as the bearing shell 2.

As is shown in the sectional view according to FIG. 4, the fixing of the bearing shells 2 on the housing 5 is provided by means of interlocking. It allows a certain displacement or movement of the individual bearing shell 2.

The curvature of the individual bearing shell 2 is variable. For this purpose, a packing plate or a strip of another material (not shown) can be inserted as a spacer element between the bearing shell 2 and the housing 5. The bearing shell 2 is preferably mounted at virtually three points, as seen in an axially perpendicularly sectional view: on the one hand, at both of its ends (as seen in the circumferential direction) by means of the shell holder 6, and on the other hand in a middle region by the packing plate.

FIG. 4 further shows that the holding strip 6.1 is offset relative to the inner jacket surface of the bearing shell 2. It therefore has a distance from the jacket surface of the shaft (not shown) in order to avoid contact with said shaft.

Instead, the device shown in FIG. 5 can also be considered.

FIG. 5 again shows a housing 5 with a completely shown shell 2, adjacent to which there are two further shells 2 on either side, which are only partly shown here.

An adjusting device 7 is provided for setting the curvature of the shell 2. It comprises a pin 7.1, at the radially inner end of which a bar 7.2 is provided. The bar 7.2 is embedded in the material of the shell 2. The pin 7.1 protrudes beyond the radially outer jacket surface of the housing 5. It carries a thread there, onto which a nut 7.3 is screwed. The radial position of the bar 7.2 can be varied by means of the nut 7.3. The curvature of the shell 2 can be adjusted in this way. The adjusting device fulfils both the function of the spacer element and also the function of the clamping or holding element.

The device for adjusting the curvature of the bearing shell is preferably located in the centre between the two circumferential ends of the respective bearing shell.

LIST OF REFERENCE NUMERALS

-   1 Shaft -   1.1 Jacket surface of the shaft -   2 Bearing, bearing shell -   2.1 Bearing surface -   3 Bearing clearance -   4 Pressure field -   5 Housing -   6 Shell holder -   6.1 Holding strip -   6.2 Holding pin -   6.3 Screw -   7 Adjusting device -   7.1 Adjusting pin -   7.2 Bar -   7.3 Nut 

1-6. (canceled)
 7. A radial bearing for mounting a shaft, the radial bearing comprising: several bearing shells which are curved according to the radius of the shaft and whose inner surface forms the plain bearing surfaces; a housing enclosing the bearing shells; each bearing shell is clamped to the housing at least in the region of its two circumferential ends; means for setting the curvature of the individual bearing shell; the means for setting the curvature of the bearing shells respectively comprise a bar which is embedded in the material of the bearing shell, further a pin which is guided through the housing, acts with its radially inner end on the bar, and comprises at its radially outer end an engagement element for displacing the pin and the bar.
 8. The radial bearing according to claim 7, wherein the bearing shells consist of plastic or metal or any other flexible material.
 9. The radial bearing according to claim 8, wherein the bearing shells are brought to their final shape relevant for the bearing function only during mounting.
 10. The radial bearing according to claim 9, wherein the bearing shells are mounted by means of at least one clamping or holding element and at least one spacer element, with both the bearing slackness and also the segment shell curvature being set during mounting both via the position and the selection of the spacer and the clamping or holding element.
 11. The radial bearing according to claim 7, wherein: a shell holder is provided between two mutually adjacent bearing shells; each shell holder comprises a holding strip which extends over the axial length of the radial bearing or over a relevant part of its length and is inserted into recesses of the bearing shells; the holding strip is fixed to holding pins which are guided through the remaining part of the thickness of the bearing shells and through the housing and are fixed to the outer jacket surface of the housing.
 12. The radial bearing according to claim 8, wherein: a shell holder is provided between two mutually adjacent bearing shells; each shell holder comprises a holding strip which extends over the axial length of the radial bearing or over a relevant part of its length and is inserted into recesses of the bearing shells; the holding strip is fixed to holding pins which are guided through the remaining part of the thickness of the bearing shells and through the housing and are fixed to the outer jacket surface of the housing.
 13. The radial bearing according to claim 9, wherein: a shell holder is provided between two mutually adjacent bearing shells; each shell holder comprises a holding strip which extends over the axial length of the radial bearing or over a relevant part of its length and is inserted into recesses of the bearing shells; the holding strip is fixed to holding pins which are guided through the remaining part of the thickness of the bearing shells and through the housing and are fixed to the outer jacket surface of the housing.
 14. The radial bearing according to claim 10, wherein: a shell holder is provided between two mutually adjacent bearing shells; each shell holder comprises a holding strip which extends over the axial length of the radial bearing or over a relevant part of its length and is inserted into recesses of the bearing shells; the holding strip is fixed to holding pins which are guided through the remaining part of the thickness of the bearing shells and through the housing and are fixed to the outer jacket surface of the housing.
 15. The radial bearing according to claim 11, wherein the radially inner surfaces of the holding strips lie radially outside of the inner jacket surfaces of the bearing shells.
 16. The radial bearing according to claim 12, wherein the radially inner surfaces of the holding strips lie radially outside of the inner jacket surfaces of the bearing shells.
 17. The radial bearing according to claim 13, wherein the radially inner surfaces of the holding strips lie radially outside of the inner jacket surfaces of the bearing shells.
 18. The radial bearing according to claim 14, wherein the radially inner surfaces of the holding strips lie radially outside of the inner jacket surfaces of the bearing shells. 